MSM-04 Acguy

By Jenxi Seow



MSM-04 Acguy

The MSM-04 Acguy was an amphibious mobile armour mass produced by the Principality of Zeon. The “MS” in the model code refers to it being a mobile suit, while the “M” identifies it as a marine model. The “04” in the model code indicates that it was the fourth design in the line.


During the One Year War, the Principality of Zeon started to push its ground offensive on Earth. It had developed the MS-09 Dom for ground use, but its fusion reactor was unable to power mega particle weaponry. A fusion reactor with sufficient power output would require a more efficient cooling system, and the solution Zeon identified was to use seawater as a coolant. This meant developing an amphibious mobile suit.

Besides allowing the use of mega particle weaponry, such a suit would also allow Zeon to gain sea superiority and advance its territories on Earth.

On the back of its successful MS-06 Zaku II models, the Zeonic Company developed the MS-06M Zaku Marine Type variant for underwater combat. However, it proved to be a failure when deployed in battle. Thus, Zeon command ordered the MIP Company and the Zimmad Company to develop an amphibious mobile suit.

Instead of modifying an existing mobile suit, the Zimmad Company decided to design an amphibious mobile suit from scratch. The company developed the MSM-03 Gogg and it revolutionised Zeon’s approach to underwater combat.

The Zimmad Company’s success prompted the Zeonic Company to apply the same concepts and they developed the MSM-04 Acguy.

On 30 November UC 0079, a squadron of Acguy units led by Zeon ace pilot Char Aznable infiltrated the Earth Federation underground base Jaburo. Although the squadron failed to achieve its objective of destroying the Federation’s mobile suit factory, their successful infiltration highlighted the Acguy’s stealth abilities.

MSM-04 Acguy

Production overview

Model number: MSM-04

Code name: Acguy

Type: Mass production amphibious mobile suit

Completed: UC 0079

First deployment: 22 August UC 0079

Manufacturer: Zeonic Company

Operator: Principality of Zeon, civilians

Developed from:

MSM-04-1 Prototype Acguy

Developed into:

MSM-04G Juaggu

MSM-04N Agguguy


MSM-04 Acguy Heavy Firepower Type

General characteristics

Crew: Pilot only

Cockpit: Standard with linear seat cockpit in torso

Head height: 19.2 m

Total height: Unknown

Empty weight: 91.6 t

Gross weight: 129.0 t

Armour: Super hard steel alloy

Sensors: Standard

Sensor range: 5,400 m


Power plant: Minovsky type ultracompact fusion reactor

Power output: 1,870 kW


‣ Hydrojet thrusters: 109,600 kg total

Max speed: 53 knots (water), 80 km/h (ground)

180° turn time: Unknown

Thrust-to-weight ratio: 0.85 G



‣ 4 x 105 mm vulcan gun

‣ 1 x retractable claw

‣ 1 x six-tube rocket launcher


‣ 1 x mega particle cannon

‣ 1 x double-barrel machine gun

‣ 1 x 120 mm machine gun with flamethrower

‣ 1 x arm shield


‣ 1 x Heat Hawk

‣ 1 x cross shield


The MS-06M Zaku Marine Type was the first underwater-use mobile suit used by the Principality of Zeon. However, being a modified MS-06F Zaku II, the Zaku Marine Type performed poorly and was condemned as a failed model. The success of the MSM-03 Gogg designed by the Zimmad Company prompted the Zeonic Company to create a design with the same concepts.

The MSM-04 Acguy was designed to use internal parts from the Zaku II, another mobile suit from the Zeonic Company. This would allow faster and more cost-efficient mass production of the mobile suit.

The Acguy was powered by two Zaku II Minovsky fusion reactors. Despite the powerful reactors, the Acguy used sea water as a heat sink to allow it to maintain relatively low heat signatures. This made the Acguy ideal for covert operations. It could also equip mega particle weaponry.

The body of the mobile suit contained ballast tanks that it used to surface and dive. Water in the tanks radiated reactor heat when the mobile suit was out of the water.

It used hydrojet thrusters with a total output of 109,600 kg for propulsion. The maximum speed of the Acguy was 80 km/h on land and 53 knots in water.

The mobile suit used a modular forearm system that allowed it to switch its weapons. This allowed different Acguy units to be suited for different combat situations, making a team of these mobile suits a versatile strike force.

Like the other Zeon mobile suits of its time, the Acguy had super hard steel alloy armour. It had a standard cockpit in its torso. The cockpit was later refitted with linear seat with panoramic monitor in its body. Its standard sensors with detection range of 5,400 metres.

The Acguy could use optional equipment for reconnaissance. It could mount a visor over its monoeye. This linked with a topographical scanning unit mounted on the left arm and a periscope mounted on its back. The periscope helped obtain optical feed from the surface when the Acguy was still submerged in water.


The Acguy equipped ranged weapons on its forearm and used a claw for close range combat. It had interchangeable forearms that allowed it to swap to other fixed weapons depending on the mission requirements.

Vulcan guns

The Acguy had four fire-linked 105 mm vulcan guns mounted in on its head. They were used primarily against light-armoured support units. Sustained fire from the guns could damage mobile suits and were often used in close distance combat.

Six-tube rocket launcher

The Acguy had a six-tube rocket launcher built into its left arm. These were used for medium to long range attack.

Retractable claw

The right arm of the Acguy had a retractable claw. The claw was used in melee combat. The claw could be used to grip onto the enemy to allow point-blank attacks from the mega particle cannon or machine gun.

MSM-04 Acguy claw

Mega particle cannon

In the centre of the Acguy’s right forearm, there was mega particle cannon built into it. This drew power directly from the these guns drew energy directly from the mobile suit’s powerful reactors.

They were cooled by the sea water so they could be fired rapidly without risk of overheating. However, this worked only if the Acguy remained in the water. The pilot had to be wary of overheating when using the guns while the Acguy was out of water.

Double-barrel machine gun

A double-barrel machine gun module could replace the mega particle cannon module in the Acguy’s right forearm. This allowed the mobile suit to use projectile weaponry instead of particle weaponry.

120 mm machine gun with flamethrower

The Acguy could also mount a ZMP-50D machine gun developed specifically for the Zaku II line. It was drum-fed with 100 rounds per drum. Additional drums were usually carried on the back of another Acguy unit

The machine gun could attach a flamethrower module.

Heat Hawk

The Acguy could wield a modified Heat Hawk with its retractable claw on the right arm. It dealt devastating devastating slashing damage in close range with the superheated blade.

Cross shield

The retractable claw on the right arm could also wield a cross shield. It was able to block most ballistic and explosive projectiles. This was preferred when the Acguy deployed with ranged weapon.

Sleeve shield

For a close combat load out, the Acguy could equip a sleeve shield over its left arm module. This allowed it to parry melee attacks without sacrificing its rocket launcher. The shield was able to block most ballistic and explosive projectiles.

Known pilots


Behind the scenes

Kunio Okawara was the original mechanical designer. Kimitoshi Yamane designed the version in Mobile Suit Gundam: The 08th MS Team. Yasuo Ohtagaki designed the version in the Mobile Suit Gundam Thunderbolt manga.